Carbon nanotubes are considered one of the most promising materials of the post-Moore's law era because of its excellent electrical properties and stability. The intrinsic carbon nanotube is around ⅔ of semi-conducting nature and ⅓ of metallic nature, and the range of application of nanotubes as a transistor channel material is limited due to their metallic nature.
In recent years, mesh-like carbon nanotube thin film transistors manufactured based on solution separation and purification technology has drawn more and more attention. This is because carbon nanotubes with as high as 99%-99.9% of semi-conductive nature can be manufactured through the solution separation and purification technology. Furthermore, the charge carriers need to be transmitted from the source electrode to the drain electrode through a plurality of carbon nanotubes in the carbon nanotube thin film transistor mesh, and as such, the negative impacts of the metallic nature of carbon nanotubes on the current on-off ratios (or current switching ratios) can be overcome.
However, as shown in FIG. 1, which illustrates an electron microscope image of the distribution of carbon nanotubes in the channel of existing thin film transistor, the distribution of carbon nanotubes in the carbon nanotube mesh is generally unordered. As such, the number of nodes over the channel between the source electrode and the drain electrode is large, the node resistance is large, and as a result, the on-state current and the carrier mobility are relatively small.
It can be appreciated, although the performance of the mesh-like carbon nanotube transistor is better than amorphous silicon and organic thin film materials, there is still a large distance from the intrinsic performance of the carbon nanotube. Therefore, how to improve the performance of the mesh-like carbon nanotube thin film transistors is an urgent problem waiting to be solved.